\(Ư( - 2) =\) \(\left\{ { - 2; - 1;\,1;\,2} \right\}\)
\(Ư(4) =\) \(\left\{ { - 4; - 2; - 1;\,1;\,2;\,4} \right\}\)
\(Ư(13) = \)\(\left\{ { - 13; - 1;\,1;\,13} \right\}\)
\(Ư(15) = \)\(\left\{ { - 15; - 5; - 3; - 1;\,1;\,3;\,5;\,15} \right\}\)
\(Ư(1) = \)\(\left\{ { - 1;\,1} \right\}\)
